install to PREFIX if defined, make tests dir before install..

This gets things working sanely for packaging...

Makefile.inc

@@ -1,4 +1,11 @@
 # This is to replicate the other parts of the FreeBSD build infrastructure.
 
+.if defined(PREFIX)
+BINDIR?=        ${PREFIX}/sbin
+SHAREDIR?=      ${PREFIX}/share
+TESTSBASE?=     ${PREFIX}/tests
+.else
 BINDIR?=	/sbin
+.endif
+
 WARNS?= 6

tests/Makefile

@@ -2,8 +2,12 @@
 
 PACKAGE=	tests
 
-TESTSDIR=	${TESTSBASE}/sys/geom/class/gate
+TESTSDIR=	${TESTSBASE}/sbin/ggatessh
+DIRS+=		${TESTSDIR}
 
 ATF_TESTS_SH+=	ggatessh_test
 
+# make sure dirs are created
+beforeinstall: installdirs
+
 .include <bsd.test.mk>